Holloway impregnates Dr. Shaw with a creature that grows to be a ginormous facehugger

The ginormous facehugger implants an egg into the chest of one of the Engineers

The egg hatches into an alien

Is the alien as we know it the inevitable consequence of the black liquid, or would a different type of creature have resulted if a different bunch of individuals / species were involved in the process.

I note you have undone my edit. I added those spoiler tags, as the steps you have outlined are, well, spoilers!
– Often RightAug 20 '15 at 4:45

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@N_Soong I didn't like the formatting you applied. Also, the movie came out over three years ago.
– user50863Aug 20 '15 at 8:34

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@LV-426 It doesn't matter how long ago the movie came out, there will still be people who haven't seen it. As far as I am aware, we are meant to err on the side of caution when it comes to spoilers.
– Dr R DizzleAug 20 '15 at 9:08

2 Answers
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It seems the alien is an inevitable consequence of the black liquid, but it does take on some of the qualities of the species it hatches in. The aliens born from humans look a bit different (more humanoid) than e.g. the alien from Alien 3 (bursts out of a dog and is a bit more animalistic) or the one at the end Prometheus (which comes out of the Engineer).

Or the one in predator vs alien which comes out of a predator and looks far more predator-like. Now I want to see some iddy biddy mouse-aliens with terrifying black alien skin and little twitchy mouse noses.
– MurphyAug 20 '15 at 12:58

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@Murphy You get to see an iddy bity bug alien in the intro in the extended intro sequence to Alien Ressurection. Makes absolutely zero sense at all, but it's there and gets a closeup on it's mandibles.
– Mikey MouseAug 21 '15 at 14:47

The Black Goo is called Chemical A0-3959X.91 – 15. It is a virulent mutagenic pathogen that, when consumed, causes the hosts cells to mutate. This suggests that the host is a necessary parameter in the mutation, and, as such, the host's genetic make-up could affect the outcome of the Human (or non-human) hybrid.

It is not known if his [Holloway's] sperm was mutated causing an
abnormal conception or if he was simply carrying a Trilobite that
moved into Shaw, though the latter seems more probable given that Shaw
was sterile. Whether Trilobites prefer to move into female subjects or
if Holloway would have naturally given "birth" to the Trilobite is
unknown.

Although Shaw was exposed to the infected Holloway and had sex with
him, she was not infected with the liquid and only received the
Trilobite embryo. This suggests that the Black Liquid itself is not
sexually transmitted, but it affects the host's reproductive system